feat: complete session — catalog, marketplace, WhatsApp, peer-to-peer, install scripts

Major features:
- Pixel-Perfect glassmorphism design (landing + POS + public catalog)
- OEM/Local catalog toggle with Nexpart taxonomy (14 groups, 108 subgroups, 558 part types)
- Marketplace B2B Phase 1 (bodegas, POs, status machine, WA+email notifications)
- Peer-to-peer inventory (multi-instance, LAN discovery)
- WhatsApp: photo→Vision AI, voice→Whisper, conversational quotations
- Smart unified search (VIN/plate/part_number/keyword auto-detect)
- Shop Supplies tab (vehicle-independent parts)
- Chatbot AI fallback chain (5 models) + response cache
- CSV inventory import tool + setup_instance.sh installer
- Tablet-responsive CSS + sidebar toggle
- Filters, export CSV, employee edit, business data save
- Quotation system (WA→POS) with auto-print on confirmation
- Live stats on landing page

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

sql/marketplace_tenant_users.sql

@@ -0,0 +1,16 @@
+-- ═══════════════════════════════════════════════════════════════════════
+-- Marketplace — per-tenant employees table migration
+-- Apply to: tenant_template, tenant_refaccionaria_demo, tenant_acct_test,
+-- and any future tenant DB.
+-- ═══════════════════════════════════════════════════════════════════════
+
+ALTER TABLE employees
+    ADD COLUMN IF NOT EXISTS marketplace_role VARCHAR(20) NOT NULL DEFAULT 'buyer',
+    ADD COLUMN IF NOT EXISTS bodega_id INTEGER;
+
+-- Valid values: 'buyer' (refaccionaria/taller) | 'seller' (bodega) | 'admin'
+-- bodega_id references master.bodegas(id_bodega). No FK because that table
+-- lives in a different database — the app enforces referential integrity.
+
+CREATE INDEX IF NOT EXISTS idx_employees_marketplace_role ON employees (marketplace_role);
+CREATE INDEX IF NOT EXISTS idx_employees_bodega ON employees (bodega_id) WHERE bodega_id IS NOT NULL;